[PATCH 14/27] libcamera: software_isp: egl: Introduce an eGL base helper class

Bryan O'Donoghue bryan.odonoghue at linaro.org
Tue Apr 22 23:59:07 CEST 2025


Introduce an eGL base helper class which provides an eGL context based on a
passed width and height.

The initGLContext function could be overloaded to provide an interface to a
real display.

A set of helper functions is provided to compile and link GLSL shaders.
linkShaderProgram currently compiles vertex/fragment pairs but could be
overloaded or passed a parameter to link a compute shader instead.

Breaking the eGL interface away from debayering - allows to use the eGL
context inside of a dma-buf heap cleanly, reuse that context inside of a
debayer layer and conceivably reuse the context in a multi-stage shader
pass.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue at linaro.org>
---
 src/libcamera/software_isp/egl.cpp | 346 +++++++++++++++++++++++++++++
 src/libcamera/software_isp/egl.h   | 106 +++++++++
 2 files changed, 452 insertions(+)
 create mode 100644 src/libcamera/software_isp/egl.cpp
 create mode 100644 src/libcamera/software_isp/egl.h

diff --git a/src/libcamera/software_isp/egl.cpp b/src/libcamera/software_isp/egl.cpp
new file mode 100644
index 00000000..c3eb8290
--- /dev/null
+++ b/src/libcamera/software_isp/egl.cpp
@@ -0,0 +1,346 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Linaro Ltd.
+ *
+ * Authors:
+ * Bryan O'Donoghue <bryan.odonoghue at linaro.org>
+ *
+ * egl.cpp - Helper class for managing eGL interactions.
+ */
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <linux/dma-buf.h>
+#include <linux/dma-heap.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include "egl.h"
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(eGL)
+
+eGL::eGL()
+{
+}
+
+eGL::~eGL()
+{
+}
+
+// Create linear image attached to previous BO object
+int eGL::createDMABufTexture2D(eGLImage *eglImage, int fd)
+{
+	int ret = 0;
+
+	eglImage->stride_ = eglImage->width_ * eglImage->height_;
+	eglImage->offset_ = 0;
+	eglImage->framesize_ = eglImage->height_ * eglImage->stride_;
+
+	LOG(eGL, Info) << __func__ << " stride " << eglImage->stride_ << " width " << eglImage->width_ <<
+			" height " << eglImage->height_ << " offset " << eglImage->offset_ << " framesize " <<
+			eglImage->framesize_;
+
+	// TODO: use the dma buf handle from udma heap here directly
+	// should work for both input and output with fencing
+	EGLint image_attrs[] = {
+		EGL_WIDTH, (EGLint)eglImage->width_,
+		EGL_HEIGHT, (EGLint)eglImage->height_,
+		EGL_LINUX_DRM_FOURCC_EXT, (int)GBM_FORMAT_ARGB8888,
+		EGL_DMA_BUF_PLANE0_FD_EXT, fd,
+		EGL_DMA_BUF_PLANE0_OFFSET_EXT, 0,
+		EGL_DMA_BUF_PLANE0_PITCH_EXT, (EGLint)eglImage->framesize_,
+		EGL_NONE, EGL_NONE,	/* modifier lo */
+		EGL_NONE, EGL_NONE,	/* modifier hi */
+		EGL_NONE,
+	};
+
+	eglImage->image_ = eglCreateImageKHR(display_, EGL_NO_CONTEXT,
+						   EGL_LINUX_DMA_BUF_EXT,
+						   NULL, image_attrs);
+
+	if (eglImage->image_ == EGL_NO_IMAGE_KHR) {
+		LOG(eGL, Error) << "eglCreateImageKHR fail";
+		ret = -ENODEV;
+		goto done;
+	}
+
+	// Generate texture, bind, associate image to texture, configure, unbind
+	glEGLImageTargetTexture2DOES(GL_TEXTURE_2D, eglImage->image_);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+done:
+	return ret;
+}
+
+void eGL::destroyDMABufTexture(eGLImage *eglImage)
+{
+	eglDestroyImage(display_, eglImage->image_);
+}
+
+//
+// Generate a 2D texture from an input buffer directly
+void eGL::createTexture2D(eGLImage *eglImage, uint32_t width, uint32_t height, void *data)
+{
+	glBindTexture(GL_TEXTURE_2D, eglImage->texture_);
+
+	// Generate texture, bind, associate image to texture, configure, unbind
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width, height, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, data);
+
+	// Nearest filtering
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+	// Wrap to edge to avoid edge artifacts
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+}
+
+int eGL::initEGLContext(GBM *gbmContext)
+{
+	EGLint configAttribs[] = {
+		EGL_RED_SIZE, 8, 
+		EGL_GREEN_SIZE, 8,
+		EGL_BLUE_SIZE, 8,
+		EGL_ALPHA_SIZE, 8,
+		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
+		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
+		EGL_NONE
+	};
+
+	EGLint contextAttribs[] = {
+		EGL_CONTEXT_MAJOR_VERSION, 2,
+		EGL_NONE
+	};
+	EGLint numConfigs;
+	EGLConfig config;
+	EGLint major;
+	EGLint minor;
+
+	if (!eglBindAPI(EGL_OPENGL_ES_API)) {
+		LOG(eGL, Error) << "API bind fail";
+		goto fail;
+	}
+
+	//TODO: use optional eglGetPlatformDisplayEXT ?
+	display_ = eglGetDisplay(gbmContext->getDevice());
+	if (display_ == EGL_NO_DISPLAY) {
+		LOG(eGL, Error) << "Unable to get EGL display";
+		goto fail;
+	}
+
+	if (eglInitialize(display_, &major, &minor) != EGL_TRUE) {
+		LOG(eGL, Error) << "eglInitialize fail";
+		goto fail;
+	}
+
+	LOG(eGL, Info) << "EGL: version " << major << "." <<  minor;
+	LOG(eGL, Info) << "EGL: EGL_VERSION: " << eglQueryString(display_, EGL_VERSION);
+	LOG(eGL, Info) << "EGL: EGL_VENDOR: " << eglQueryString(display_, EGL_VENDOR);
+	LOG(eGL, Info) << "EGL: EGL_CLIENT_APIS: " << eglQueryString(display_, EGL_CLIENT_APIS);
+	LOG(eGL, Info) << "EGL: EGL_EXTENSIONS: " << eglQueryString(display_, EGL_EXTENSIONS);
+
+	//TODO: interrogate strings to make sure we aren't hooking unsupported functions
+	//      and remember to error out if a function we depend on isn't found.
+	eglCreateImageKHR = (PFNEGLCREATEIMAGEKHRPROC)eglGetProcAddress("eglCreateImageKHR");
+	eglDestroyImageKHR = (PFNEGLDESTROYIMAGEKHRPROC)eglGetProcAddress("eglDestroyImageKHR");
+	eglExportDMABUFImageMESA = (PFNEGLEXPORTDMABUFIMAGEMESAPROC)eglGetProcAddress("eglExportDMABUFImageMESA");
+	glEGLImageTargetTexture2DOES = (PFNGLEGLIMAGETARGETTEXTURE2DOESPROC)eglGetProcAddress("glEGLImageTargetTexture2DOES");
+	eglClientWaitSyncKHR = (PFNEGLCLIENTWAITSYNCKHRPROC)eglGetProcAddress("eglClientWaitSyncKHR");
+	eglCreateSyncKHR = (PFNEGLCREATESYNCKHRPROC)eglGetProcAddress("eglCreateSyncKHR");
+
+	if (eglChooseConfig(display_, configAttribs, &config, 1, &numConfigs) != EGL_TRUE) {
+		LOG(eGL, Error) << "eglChooseConfig fail";
+		goto fail;
+	}
+
+	context_ = eglCreateContext(display_, config, EGL_NO_CONTEXT, contextAttribs);
+	if (context_ == EGL_NO_CONTEXT) {
+		LOG(eGL, Error) << "eglContext returned EGL_NO_CONTEXT";
+		goto fail;
+	}
+
+	surface_ = eglCreateWindowSurface(display_, config,
+					  (EGLNativeWindowType)gbmContext->getSurface(),
+					  NULL);
+	if (surface_ == EGL_NO_SURFACE) {
+		LOG(eGL, Error) << "eglCreateWindowSurface fail";
+		goto fail;
+	}
+
+	makeCurrent();
+	swapBuffers();
+
+	return 0;
+fail:
+
+	return -ENODEV;
+}
+
+void eGL::makeCurrent(void)
+{
+	if (eglMakeCurrent(display_, surface_, surface_, context_) != EGL_TRUE) {
+		LOG(eGL, Error) << "eglMakeCurrent fail";
+	}
+}
+
+void eGL::swapBuffers(void)
+{
+	if (eglSwapBuffers(display_, surface_) != EGL_TRUE) {
+		LOG(eGL, Error) << "eglSwapBuffers fail";
+	}
+}
+
+void eGL::useProgram(GLuint programId)
+{
+	glUseProgram(programId);
+}
+
+void eGL::pushEnv(std::vector<std::string>& shaderEnv, const char *str)
+{
+	std::string addStr = str;
+
+	addStr.push_back('\n');
+	shaderEnv.push_back(addStr);
+}
+
+int eGL::compileVertexShader(GLuint &shaderId, unsigned char *shaderData,
+		       unsigned int shaderDataLen,
+		       std::vector<std::string> shaderEnv)
+{
+	return compileShader(GL_VERTEX_SHADER, shaderId, shaderData, shaderDataLen, shaderEnv);
+}
+
+int eGL::compileFragmentShader(GLuint &shaderId, unsigned char *shaderData,
+		       unsigned int shaderDataLen,
+		       std::vector<std::string> shaderEnv)
+{
+	return compileShader(GL_FRAGMENT_SHADER, shaderId, shaderData, shaderDataLen, shaderEnv);
+}
+
+int eGL::compileShader(int shaderType, GLuint &shaderId, unsigned char *shaderData,
+		       unsigned int shaderDataLen,
+		       std::vector<std::string> shaderEnv)
+{
+	GLchar **shaderSourceData;
+	GLint *shaderDataLengths;
+	GLint success;
+	GLsizei count;
+	size_t i;
+
+	count = 1 + shaderEnv.size();
+	shaderSourceData = new GLchar*[count];
+	shaderDataLengths = new GLint[count];
+
+	// Prefix defines before main body of shader
+	for (i = 0; i < shaderEnv.size(); i++) {
+		shaderSourceData[i] = (GLchar*)shaderEnv[i].c_str();
+		shaderDataLengths[i] = shaderEnv[i].length();
+	}
+
+	// Now the main body of the shader program
+	shaderSourceData[i] = (GLchar*)shaderData;
+	shaderDataLengths[i] = shaderDataLen;
+
+	// And create the shader
+	shaderId = glCreateShader(shaderType);
+	glShaderSource(shaderId, count, shaderSourceData, shaderDataLengths);
+	glCompileShader(shaderId);
+
+	// Check status
+	glGetShaderiv(shaderId, GL_COMPILE_STATUS, &success);
+	if (success == GL_FALSE) {
+		GLint sizeLog = 0;
+		GLchar *infoLog;
+
+		glGetShaderiv(shaderId, GL_INFO_LOG_LENGTH, &sizeLog);
+		infoLog = new GLchar[sizeLog];
+
+		glGetShaderInfoLog(shaderId, sizeLog, &sizeLog, infoLog);
+		LOG(eGL, Error) << infoLog;
+
+		delete [] infoLog;
+	}
+
+	delete [] shaderSourceData;
+	delete [] shaderDataLengths;
+
+	return !(success == GL_TRUE);
+}
+
+void eGL::dumpShaderSource(GLuint shaderId)
+{
+	GLint shaderLength = 0;
+	GLchar *shaderSource;
+
+	glGetShaderiv(shaderId, GL_SHADER_SOURCE_LENGTH, &shaderLength);
+
+	LOG(eGL, Debug) <<"Shader length is " << shaderLength;
+
+	if (shaderLength > 0) {
+		shaderSource = new GLchar[shaderLength];
+		if (!shaderSource)
+			return;
+
+		glGetShaderSource(shaderId, shaderLength, &shaderLength, shaderSource);
+		if (shaderLength) {
+			LOG(eGL, Info) << "Shader source = " << shaderSource;
+		}
+		delete [] shaderSource;
+	}
+}
+
+int eGL::linkProgram(GLuint &programId, GLuint vertexshaderId, GLuint fragmentshaderId)
+{
+	GLint success;
+	GLenum err;
+
+	programId = glCreateProgram();
+	if (!programId)
+		goto fail;
+
+	glAttachShader(programId, vertexshaderId);
+	if ((err = glGetError()) != GL_NO_ERROR) {
+		LOG(eGL, Error) << "Attach compute vertex shader fail";
+		goto fail;
+	}
+
+	glAttachShader(programId, fragmentshaderId);
+	if ((err = glGetError()) != GL_NO_ERROR) {
+		LOG(eGL, Error) << "Attach compute vertex shader fail";
+		goto fail;
+	}
+
+	glLinkProgram(programId);
+	if ((err = glGetError()) != GL_NO_ERROR) {
+		LOG(eGL, Error) << "Link program fail";
+		goto fail;
+	}
+
+	glDetachShader(programId, fragmentshaderId);
+	glDetachShader(programId, vertexshaderId);
+
+	// Check status
+	glGetProgramiv(programId, GL_LINK_STATUS, &success);
+	if (success == GL_FALSE) {
+		GLint sizeLog = 0;
+		GLchar *infoLog;
+
+		glGetProgramiv(programId, GL_INFO_LOG_LENGTH, &sizeLog);
+		infoLog = new GLchar[sizeLog];
+
+		glGetProgramInfoLog(programId, sizeLog, &sizeLog, infoLog);
+		LOG(eGL, Error) << infoLog;
+
+		delete [] infoLog;
+		goto fail;
+	}
+
+	return 0;
+fail:
+	return -ENODEV;
+}
+}
diff --git a/src/libcamera/software_isp/egl.h b/src/libcamera/software_isp/egl.h
new file mode 100644
index 00000000..f3c5d50f
--- /dev/null
+++ b/src/libcamera/software_isp/egl.h
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Linaro Ltd.
+ *
+ * Authors:
+ * Bryan O'Donoghue <bryan.odonoghue at linaro.org>
+ *
+ * egl_context.cpp - Helper class for managing eGL interactions.
+ */
+
+#pragma once
+
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#define EGL_EGLEXT_PROTOTYPES
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+#include <GLES3/gl32.h>
+
+#include <libcamera/base/log.h>
+
+#include <unistd.h> // close
+
+#include "gbm.h"
+
+namespace libcamera {
+
+LOG_DECLARE_CATEGORY(eGL)
+
+class eGLImage {
+public:
+	eGLImage(uint32_t width, uint32_t height, uint32_t bpp) {
+		image_ = EGL_NO_IMAGE_KHR;
+		width_ = width;
+		height_ = height;
+		bpp_ = bpp;
+		stride_ = width_ * bpp_ / 4;
+		framesize_ = stride_ * height_;
+
+		glGenTextures(1, &texture_);
+	}
+
+	~eGLImage() {
+		glDeleteTextures(1, &texture_);
+	};
+
+	GLuint texture_;
+	EGLImageKHR image_;
+	uint32_t width_;
+	uint32_t height_;
+	uint32_t stride_;
+	uint32_t offset_;
+	uint32_t framesize_;
+	uint32_t bpp_;
+};
+
+class eGL
+{
+public:
+	eGL();
+	~eGL();
+
+	int initEGLContext(GBM *gbmContext);
+	int createDMABufTexture2D(eGLImage *eglImage, int fd);
+	void destroyDMABufTexture(eGLImage *eglImage);
+	void createTexture2D(eGLImage *eglImage, uint32_t width, uint32_t height, void *data);
+	void createTexture1D(eGLImage *eglImage, uint32_t width, void *data);
+
+	void pushEnv(std::vector<std::string> &shaderEnv, const char *str);
+	void makeCurrent();
+	void swapBuffers();
+
+	int compileVertexShader(GLuint &shaderId, unsigned char *shaderData,
+			  	unsigned int shaderDataLen,
+			  	std::vector<std::string> shaderEnv);
+	int compileFragmentShader(GLuint &shaderId, unsigned char *shaderData,
+			  	unsigned int shaderDataLen,
+			  	std::vector<std::string> shaderEnv);
+	int linkProgram(GLuint &programIdd, GLuint fragmentshaderId, GLuint vertexshaderId);
+	void dumpShaderSource(GLuint shaderId);
+	void useProgram(GLuint programId);
+
+private:
+	int fd_;
+
+	EGLDisplay display_;
+	EGLContext context_;
+	EGLSurface surface_;
+
+	int compileShader(int shaderType, GLuint &shaderId, unsigned char *shaderData,
+			  unsigned int shaderDataLen,
+			  std::vector<std::string> shaderEnv);
+
+	PFNEGLEXPORTDMABUFIMAGEMESAPROC eglExportDMABUFImageMESA;
+	PFNGLEGLIMAGETARGETTEXTURE2DOESPROC glEGLImageTargetTexture2DOES;
+
+	PFNEGLCREATEIMAGEKHRPROC eglCreateImageKHR;
+	PFNEGLDESTROYIMAGEKHRPROC eglDestroyImageKHR;
+
+	PFNEGLCLIENTWAITSYNCKHRPROC eglClientWaitSyncKHR;
+	PFNEGLCREATESYNCKHRPROC eglCreateSyncKHR;
+protected:
+
+};
+
+};
-- 
2.49.0



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